Abstrak Ketersediaan bahan bakar fosil untuk penggerak kendaaran bermotor semakin menipis, akibat bertambah kendaraan yang beroperasi di jalan raya, sehingga perlu pemikiran energy terbarukan lai sebagai alternatif penggantinya,  Alternatif tumbuhan yaitu singkong sebagai sumber energi sebagai penggantinya perlu pemikiran lanjut. Bioethanol dari singkong ini dilakukan dengan proses fermentasu selama 5 hari dengan dicampu ragi, Tujuan menentukan daya dan torsi terbesar serta sfc terkecil saat menggunakan campuran bioetanol E10, E15 dan E20 dengan pertalite. Metode pengujian daya dan torsi sesuai standar ISO 1585 untuk mendapatkann data, selanjutnya diolah menggunakan statistik. Variabel tetapnya bioetanol (E10, E15 dan E20). Variabel berubahnya daya, torsi, konsumsi bahan bakar spesifik (sfc) dan putaran mesin. Hasil daya terbesar saat menggunakan E10 sebesar 6,67hP dan torsinya 6,58hP sedang untuk E15 dayanya sebesar 6,10hP torsinya 6,22Nm serta untuk E-20 dayanya 6,18hP torisnya 6,36Nm. Sfc terkecil untuk E10 sebesar 0,0120kg/hP,jam dan untuk E15 sebesar 0,0232kg/hP.jam serta untuk E20 sebesar 0,202kg/hp.jam. Kata kunci: bioetanol, daya, konsumsi bahan bakar Abstract The availability of traditional fuels for driving motorized vehicles is running low, due to the increasing number of vehicles operating on the highway, so it is necessary to think about other renewable energy as an alternative replacement. Namely cassava plants as an alternative energy sources as a replacement needs to be thought further. This bioethanol from cassava is obtained through a fermentation process for 5 days mixed with yeast. The aim is to determine the biggest power and torque as well as the smallest SFC when pertalite is mixed with bioethanol E10, E15 and E20. The power and torque testing method is according to ISO 1585 standard to obtain data, then it is processed statistically. The fixed variable is bioethanol (E10, E15 and E20). Free variable is changes in power, torque, specific fuel consumption (SFC) and engine speed. The biggest power is 6.67hP reached when using the E10 while the torque is 6.58hP, when using the E15 the power is 6.10hP and the torque is 6.22Nm then for the E-20 the power is 6.18hP the torque is 6.36Nm. The smallest SFC is 0.0120kg / Hp.hour for E10 and 0.0232kg / hP.hours for E15 then 0.202kg / hp.h for E20. Keywords : bioethanol,  power,  fuel consumption

This study aimed to determine the correlation value against the value of hard carbon steel with elasticity it. This is done by determining the formula formulation in the form of the regression equation Y = AX1 + BX2. Data taken from the sample used in the form of a cylindrical rod test specimens and the steel plate. Severity using the Brinell test, whereas withdrawal using tensile testing machine. The results were obtained for cylindrical steel Y = 2,41 X1 – 0,4347X2 and for specimens of steel plate (flat) Y = 2,35 X1 – 0,534X2. Y is the value of the rigidity, and X1 is hardness of steel. While X2 arises from material stretch factor. Probability influence of workmanship and style fluctuate respectively 0,4347 and 0,534 is much larger than 0.05 (a standard which is commonly used). This means that the regression coefficient is not significantly different effect. Decrease in strength may be due to the loss of influence of the stress concentration occurs. In addition it could also be due to the configuration of the carbon forming constituents uneven in areas experiencing strain due to the with drawalprocess

The use of hydro-crack systems in combustion motors in addition to functioning to improve exhaust emissions and improve engine performance through the combustion process. Perfect combustion can be adjusted during the combustion process. The purpose of the study was to determine the select magnitude of power increase, decrease fuel consumption and increase the average effective pressure and rotation of the use of 92 octane fuel without HCS. The method of testing engine performance in obtaining data is constant speed (v boarding) based on ISO 1585. Subsequent data signifies presented in a graphical form which is then calculated by statistics. Power increased 2.83hP and bmep 43.19kPa at 4000rpm, sfc dropped 0.0358kg / hP. Hours at 1000rpm and rose by 43.19kPa, when using 92 octane fuel against the standard. When using octane 95 with HCS the power rises 7.95hP at 4000rpm, buys 28.42 kPa when 4500 and sfc drop 0.0537kg / hp. Hours at 1000rpm Keywords: power, fuel consumption, effective average pressure, octane value, hydro-crack system